Felderer24: What is an EC motor?

How does the previous technology work?

Every ordinary electric motor essentially consists of two parts, the stator and the rotor. Coils are installed in the fixed stator through which electric current flows during operation. This generates a magnetic field directed at the rotor inside the motor.

With conventional AC or three-phase motors, coils or other electrically conductive materials are also used in the rotor. The magnetic field of the stator coil transfers a voltage into the rotor coil (as with the transformer). There, current also flows and another magnetic field is generated, which is attracted by the stator magnetic field. So the rotor has no other choice than to turn.

Since the magnetic field in the stator moves from coil to coil with the mains frequency (usually 50Hz), it drags the rotor with it. The problem with this technology is the high losses caused by the current flow in the rotor.

And now the EC motor. How does it work?

Ingenious technicians have created a new generation of motors, including the EC motors. The rotor of these motors consists of a permanent magnet. Therefore, it is not necessary to first transfer a voltage from the stator to the rotor in order to magnetize it. This avoids lossy current flow in the rotor. This is exactly what saves energy.

Another special feature of an EC motor is that it is operated with direct current and not with alternating or three-phase current. In order to nevertheless generate a rotating field in the stator, the individual coils of the stator must be alternately supplied with voltage by an elaborate electronic control system – the motor is therefore electronically commutated (Electronically Commutated= EC motor), and a magnetic field is created which moves from coil to coil.

The speed at which the rotating field is generated can be freely determined by the electronics and is therefore no longer dependent on the 50Hz mains frequency. This makes these motors much lighter and easier to control than conventional drives.

However, anyone who thinks that the AC motors are dying out is mistaken. Here, too, development continues, the miracle weapon of the future may be an AC machine, is called synchronous reluctance motor and, compared to a current EC motor, will be considerably more economical.

Felderer AG together with Helios Ventilatoren had invited to the fire protection seminar on 13 June 2018: “Fire protection and smoke extraction through pressure ventilation systems and mechanical smoke extraction ...

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